微專業(yè)---半導(dǎo)體制造技術(shù)課程：半導(dǎo)體工程專業(yè)英語(yǔ)ContentsSemiconductorProperties半導(dǎo)體特性01SemiconductorMaterials半導(dǎo)體材料02SemiconductorDeviceandHowTheyareUsed半導(dǎo)體器件及其使用03ProcessTechnology工藝技術(shù)04FabricationProcesses制造工藝05SemiconductorMaterialsandProcessCharacterization半導(dǎo)體材料與工藝表征06SemiconductorProperties1.1ElectricalConductivityofSolids1.2ElectricChargeCarriers1.3SemiconductorsandExternalInfluences1.4SemiconductorsinNanoscale0111Introduction

Toallowelectricalconductivity,freetomovearoundcarriersofanelectric

chargemustbeavailableinthebodyofthesolid.Concentrationofcharge

carriers(numberofcarrierspercm3),thewaytheyaregenerated,andthe

mechanismoftheirtransportacrossthesolidplaythekeyroleindefining

electricalconductivityofanysemiconductormaterial./?mek?n?z?m/機(jī)制1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricChargeCarriers載流子12TextTherearetwotypesofelectricchargecarriersinsemiconductors:electronscarryingelementarynegativechargeq

(q=1.602×10?19

coulombs),andholeswhichcarrythesamecharge,but

positive.Semiconductorsinwhichconcentrationofelectronsnexceedsconcentrationofholesp(n>>p)arereferredtoasn-type

semiconductors.Inthesamewaysemiconductorsinwhichconcentrationof

holespexceedsconcentrationofelectrons(p>>n)arereferredtoasp-type

semiconductors./?ku?lo?m/庫(kù)侖1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

13

Tomakeanygivensemiconductorn-typeorp-type,properlyselectedalienelementsneedtobeaddedtothehost

semiconductor.Theprocessisknownasdopingandalienelementsadded

arereferredtoasdopants(sometimestermimpuritiesisusedinstead).Infact,onedopantatompermillionhostatomsisenoughto

observenoticeablechangesinsemiconductor’sconductivitytypen,orp.1

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

【Controlofconductivitybydoping】/ho?st/宿主141

SemiconductorProperties半導(dǎo)體特性

1.2ElectricalConductivityofSolids固體的導(dǎo)電性1.2.1

Electronsandholesascarriersofelectriccharge電子與空穴

【Controlofconductivitybydoping】Illustrationof(a)n-typedoping(donors),(b)p-typedoping(acceptors).15

Selectionofdopantatomsisbasedonthenumberofvalanceelectrons

featuredbythehostatoms.Ifforexamplethehostatomsfeaturefour

valanceelectrons,thentheelementswithfivevalanceelectrons

needstobeintroducedintothelatticetoaddfreeelectronsandmakehost

materialn-type.Dopantatomsarereferredtoasdonorsinthiscaseand

theirconcentrationisdenotedasND.Inthecourseofthedopingprocessa

dopantatomsubstitutesforthehostatominthelatticethenusesitsfour

electronstoformcovalentbondwithadjacenthostatomsleavingonefreeelectronreadytoactasachargecarrier(Fig(a)).Undertheequilibriumconditionconcentrationofelectronsinn-typesemiconductorn=ND>>p

andelectronsareactingasmajoritycarriers.1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.1

Electronsandholesascarriersofelectriccharge/?i?kw??l?bri?m/平衡/??d?e?s(?)nt/鄰近的/m??d???r?ti/大多數(shù)/?l?t?s/晶格16

Inordertomakehostmaterialp-typeratherthann-type,dopantatoms

featuringthreevalanceelectronsareused.Inthiscase,inordertoform

acovalentbondwithadjacentatomsinthelatticedopantatomneedsto

acceptanelectronfromtheexistingbondsleavingbehindaholewhichis

freetomovearoundandtocontributetoelectricalconductivityofthehost

materialandmakingitp-type(Fig

(b)).1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.1

Electronsandholesascarriersofelectricchargep-typedoping(acceptors)17Text1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocesses(a)Generationoftheelectron-holepairasaresultofband-to-bandgeneration.

(b)annihilationoftheelectron-holepairasaresultofband-to-band

recombination./??na???le??(?)n/湮沒18

Generationandrecombinationprocessesarecontrollingtheavailabilityof

freechargecarriersinsemiconductors.Generationistheprocessoffree

chargecarriersformationinsemiconductorsresultingfromtheelectronacquiringenergyfromoutsideoftheatom,forinstancethermalenergyor

energyoflight.Theenergysuppliedtosemiconductorneedstobesufficient

toovercomeenergygapandtoallowelectron’stransitionfromthevalence

bandwhereitcannotmove,totheconductionbandwhereitcanmove,

andthus,contributetotheelectricalconductivityofthesolid.Anoutcome

oftheprocessisanemptystateleftinthevalancebandknownasahole

(Fig

(a)).1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocesses結(jié)果19

Theprocessofrecombinationisoppositetogenerationandresultsinthe

annihilationoftheelectron-holepairbyelectronsreleasingenergyequivalent

totheenergygapEgandtransitioningfromtheconductiontothevalance

bandwheretheyrecombinewithholes.1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.2

Generationandrecombinationprocessesrecombinationprocess/??na???le??(?)n/湮沒20Text1

SemiconductorProperties

1.2ElectricalConductivityofSolids1.2.3

Chargecarriersinmotion【Char